An illumination lamp including an LED (light emitting diode) has many advantages, such as that there are a carbon dioxide reducing effect and an energy saving effect, a service life is long and ultraviolet rays and heat rays are hardly generated. Therefore, the illumination lamp including the LED (called simply “LED lamp”, hereinafter) has been rapidly spreading to the market in recent years.
For instance, a conventional technology of the LED lamp is disclosed in the following Patent Literature 1.